There are often occasions where a body of water becomes polluted by the presence of floating debris, whether it be an oil or toxic waste spill in the open sea, or leaves in a swimming pool.
Owning a pool involves a great deal of maintenance, from maintaining the quality of the water to regularly removing debris such as leaves, dead insects and other pollutants. If left unattended, floating debris such as these will eventually sink to the bottom of the pool, making the task of cleaning more difficult.
Devices exist to relieve the pool owner from the burden of some of these mundane tasks. Some devices travel underwater over the walls and floor of the pool, removing scum from the surface of the walls and floor, while other devices float on the water and skim the surface to remove floating debris.
Some of these devices, although reducing the workload of the pool owner, must still be supervised, as their path of movement is easily blocked by obstacles such as other cleaning devices, floating pool accessories, and the pool walls. A number of solutions have been proposed to enable skimmers to avoid obstacles without requiring constant supervision.
U.S. Pat. No. 5,106,492 (Distinti et. al.) discloses a swimming pool skimmer having a deflection assembly comprising an arm extending in front of the skimmer. The arm is made of a resiliently flexible material, which pushes the skimmer away from any obstacle upon forced contact.
U.S. Pat. No. 4,900,432 (Arnold et. al.) discloses a swimming pool skimmer which has an electrical sensor which actuates a second motor when the sensor detects an obstacle. The thrust direction of the second motor is arranged at an angle to that of the main propulsion unit so as to change the main direction of motion of the skimmer and direct it away from the obstacle. This obviously requires additional control circuitry and additional power for the second motor, making the device complex and expensive.
In both of these prior art devices, a debris collection cavity is created within the buoyancy body of the skimmer, and debris is collected as the skimmer moves over the surface of the water by way of an impeller which also aids in scooping the debris into the catchment cavity. This arrangement has a number of disadvantages.
Firstly, with the catchment cavity disposed within the body of the skimmer, the amount of debris that can be collected is limited by the size of the body of the skimmer. A further drawback is that the impeller is arranged to make direct contact with the debris, that is, the impeller is located at the entrance to the catchment cavity, and is therefore susceptible to becoming jammed by debris.